A bending device for bending over plates for a compressor is known from EP 1 703 078 A1. The plates serve to fix compressor moving blades pushed into axial slots. Each plate is arranged between the slot bottom of the axial slot and the root of the moving blade inserted therein and in this case projects slightly beyond the axial slot on both sides. The moving blade can be locked against a displacement in the axial direction by bending over the projecting sections. To this end, the bending device is first inserted into a clearance space between two compressor disks and is secured in said clearance space by means of a restraining element. The projecting section of the plate is then bent over by actuating a radially displaceable punch.
Furthermore, the fastening of sealing plates to the side faces of turbine disks is known from GB 905 582.
Furthermore, rotors of gas turbines are known in which turbine moving blades arranged at the outer circumference in moving-blade retaining slots are locked against axial displacement by means of sealing plates. FIG. 1 shows such an arrangement in plan view and FIG. 2 shows such an arrangement in cross section along section line II-II in FIG. 1. Two adjacent sealing plates 16 are provided for each moving blade 14 to be locked against an axial displacement inside its moving-blade retaining slot 12, said sealing plates 16 each covering half the front-end opening of the moving-blade retaining slot 12. Each sealing plate 16 is inserted at its radially inner end 18 in a circumferential slot 20 provided at the front end on a rotor disk 19 and at its radially outer end 22 in a locking slot 24 which is provided on the underside 26 of a platform 28 of the moving blade 14. In order to lock each sealing plate 16 against a displacement in the circumferential direction U, a rectilinear sheet-metal strip 30 extending essentially in the radial direction of the rotor 23 is fastened to each sealing plate 16. Each sheet-metal strip 30 ends at its radially outer end 32 in an evenly converging tip 34. There are chamfered edges 36 on the platforms 28 of the moving blades 14, two opposite edges 36 of directly adjacent moving blades 14 in each case forming a recess 38 which tapers to a point and into which the tip 34 of the sheet-metal strip 30 can project for locking the sealing plates 16 against a displacement in the circumferential direction U and can bear laterally against the edges 36.
In addition, the sealing plates 16 provide for separation of two regions 37, 39 (FIG. 2) in which cooling air can occur on the one hand and an undesirable hot-gas flow can occur on the other hand.
To fasten the sheet-metal strips 30 to the sealing plate 16, two parallel slots 40, through which the sheet-metal strip 30 already pre-bent in a U shape is inserted, are provided in said sealing plate 16. That end 41 of the sheet-metal strip 30 which is opposite the tip 34 is bent into the position shown in FIG. 2 for fastening the sheet-metal strip 30 before the sealing plate 16 is fitted on the rotor disk 19.
After the fitting of the moving blades 14 in the rotor disks 19, the sealing plates 16 together with the pre-fitted sheet-metal strips 30 are successively threaded into the endlessly encircling circumferential slot 20 arranged on the rotor disk 19 and into the locking slot 24 arranged on the underside 26 of the platform 28. The sealing plates 16 are positioned along the circumference of the circumferential slot 20 in such a way that each sheet-metal strip 30 is opposite a recess 38. The tips 34 of the sheet-metal strips 30 are then bent into the recesses 38 in order to rule out the possibility of a displacement of the sealing plates 16 in the circumferential direction U.
The tip 34 of the sheet-metal strip is bent in by means of a lever 48 having a vertically adjustable prism 44. The lever 48 is placed into a groove or onto a corner of the rotor disk 19. After the prism 44 is oriented relative to the outer end 32 of the sheet-metal strip 30, the lever 48 is pressed manually against the sheet-metal strip 30, as a result of which the bending operation is initiated. The movement of the lever 48 is continued until the outer end 32 is fitted in place in the recess 38 and bears against the sealing plate 16. The bending operation is then ended.
In addition, it is known to use an essentially L-shaped sheet-metal strip for locking the sealing plate instead of a sheet-metal strip extending in the radial direction of the rotor. The L-shaped sheet-metal strip comprises a first leg which extends essentially in the circumferential direction of the rotor and a second leg which engages at the inner end of the sealing plate in an aperture provided for this purpose and arranged on the rotor.
On account of the sealing elements, displaceable in the circumferential direction, inside the circumferential slot provided in the rotor disk, it is no easy matter to bend the second leg of the L-shaped sheet-metal strip into the aperture provided for it, especially since the sheet-metal strips are also to be bent in without interruption in order to prevent work-hardening of its material in the meantime.